Vacuum-assisted sample extraction device and method

ABSTRACT

A sample extraction device and a desorption device for use in gas chromatography (GC), gas chromatography-mass spectrometry (GCMS), liquid chromatography (LC), and/or liquid chromatography-mass spectrometry (LCMS) are disclosed. In some examples, the sample extraction device includes a lower chamber holding a sorbent. The sample extraction device can extract sample headspace gas from a sample vial by placing the sorbent inside the vial and creating a vacuum to increase recovery of low volatility compounds, for example. Once the sample has been collected, the sample extraction device can be inserted into a desorption device. The desorption device can control the flow of a carrier fluid (e.g., a liquid or a gas) through the sorbent containing the sample and into a pre-column and/or a primary column of a chemical analysis device for performing GC, GCMS, LC, LCMS, and/or some other chemical analysis process.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/450,236, filed Mar. 6, 2017 and published on Sep. 14, 2017 as U.S.Publication No. 2017-0261408, which claims the benefit of U.S.Provisional Patent Application No. 62/305,468, filed on Mar. 8, 2016,the entire disclosures of which are incorporated herein by reference intheir entirety for all intended purposes.

FIELD OF THE DISCLOSURE

This relates to a sample extraction device and, more particularly, to asample extraction device for use in various chromatography techniquessuch as gas chromatography (GC), gas chromatography-mass spectrometry(GCMS), liquid chromatography (LC) and/or liquid chromatography-massspectrometry (LCMS).

BACKGROUND OF THE DISCLOSURE

GC, GCMS, LC and LCMS are techniques of performing analysis of tracechemicals in a wide range of sample matrices. In some examples, thesetechniques can be used to study biological matrices such as breath,blood, and urine; to study trace chemicals in food, water, and air; todetect odors in foods, beverages, products, and water supplies; and/orto analyze pharmaceuticals dissolved in water.

In some examples, samples for GC, GCMS, LC, and LCMS can be preparedusing solvent extraction, also known as liquid-liquid extraction.Solvent extraction can include transferring one or more solutes from afeed solution to a solvent to form an extract, which can then beanalyzed by GC, GCMS, LC, LCMS, or other analytical techniques, forexample. In some examples, headspace analysis can be another approachfor sample preparation and cleanup. Headspace analysis can includecapturing the headspace gas contained in a sample vial holding a liquidor solid sample, for example. In some examples, the liquid or solidsample can fully or partially evaporate into the headspace gas so thatwhen the headspace gas is captured, some or all of the sample iscaptured in a gaseous state. However, headspace analysis cantraditionally suffer from poor sensitivity and limited volatility rangedue to the small gas phase sample size limitations of many techniques,the inability to concentrate or “enrich” the headspace compounds priorto instrumental analysis, and the inability to further extract chemicalsout of the liquid or solid phase to enrich low volatility compounds.Thus, there exists a need for a device and method for quantitativelyextracting samples for GC, GCMS, LC, or LCMS with improved sensitivityand volatility range.

SUMMARY OF THE DISCLOSURE

This disclosure relates to a sample extraction device and, moreparticularly, to a sample extraction device for use in variouschromatography techniques such as gas chromatography (GC), gaschromatography-mass spectrometry (GCMS), liquid chromatography (LC)and/or liquid chromatography-mass spectrometry (LCMS). In some examples,the sample extraction device can be referred to as a Sorbent Pen. Thesample extraction device can contain a sorbent configured to absorb oradsorb a sample. In some examples of the disclosure, the sampleextraction device can be inserted into a sample vial to collect sampleand/or headspace gas containing the sample. A vacuum can be drawnthrough an internal seal of the sample extraction device to facilitaterapid and thorough collection of the sample, for example. In someexamples, the disclosed sample extraction techniques that occur undervacuum can be referred to as Vacuum-Assisted Sorbent Extraction, orVASE. In some examples, the sample collection device can be used at ahigher pressure, such as atmospheric pressure, inside the sample vial oroutside of the sample vial (e.g., to sample the air around the sampleextraction device).

Once the sample has been extracted, the sample extraction device can becoupled to a chemical analysis device and chemical analysis (e.g., GC,GCMS, LC, or LCMS) can occur. The sample extraction device can allow theflow of a carrier fluid (e.g., a gas or a liquid) through a sorbentcontaining the sample, and into a pre-column and/or a primary column ofa chemical analysis device configured to perform GC, GCMS, LC, LCMS,and/or some other sample analysis procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an exemplary sample extraction device, an exemplarydesorption device and an exemplary chemical analysis device forconducting chemical analysis according to examples of the disclosure.

FIG. 1B illustrates an exemplary process for performing a chemicalanalysis procedure using a sample extraction device, desorption device,chemical analysis device, and detector according to examples of thedisclosure.

FIG. 2A illustrates an exemplary sample extraction device according toexamples of the disclosure.

FIG. 2B illustrates an exemplary sample extraction device extracting asample from a sample vial according to examples of the disclosure.

FIG. 2C illustrates another exemplary sample extraction device accordingto examples of the disclosure.

FIG. 3 illustrates an exemplary process for collecting a sample andconducting chemical analysis of the sample according to examples of thedisclosure.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanyingdrawings which form a part hereof, and in which it is shown by way ofillustration specific examples that can be practiced. It is to beunderstood that other examples can be used and structural changes can bemade without departing from the scope of the examples of the disclosure.

This disclosure relates to a sample extraction device and, moreparticularly, to a sample extraction device for use in variouschromatography techniques such as gas chromatography (GC), gaschromatography-mass spectrometry (GCMS), liquid chromatography (LC)and/or liquid chromatography-mass spectrometry (LCMS). In some examples,the sample extraction device can be referred to as a Sorbent Pen. Thesample extraction device can contain a sorbent configured to absorb oradsorb a sample. In some examples of the disclosure, the sampleextraction device can be inserted into a sample vial to collect sampleand/or headspace gas containing the sample. A vacuum can be drawnthrough an internal seal of the sample extraction device to facilitaterapid and thorough collection of the sample, for example. In someexamples, the disclosed sample extraction techniques that occur undervacuum can be referred to as Vacuum-Assisted Sorbent Extraction, orVASE. In some examples, the sample collection device can be used at ahigher pressure, such as atmospheric pressure, inside the sample vial oroutside of the sample vial (e.g., to sample the air around the sampleextraction device).

Once the sample has been extracted, the sample extraction device can becoupled to a chemical analysis device and chemical analysis (e.g., GC,GCMS, LC, or LCMS) can occur. The sample extraction device can allow theflow of a carrier fluid (e.g., a gas or a liquid) through a sorbentcontaining the sample, and into a pre-column and/or a primary column ofa chemical analysis device configured to perform GC, GCMS, LC, LCMS,and/or some other sample analysis procedure.

FIG. 1A illustrates an exemplary sample extraction device 100 and anexemplary chemical analysis device 160 and detector 140 for conductingchemical analysis according to examples of the disclosure. In someexamples, chemical analysis device 160 and detector 140 can correspondto a chromatograph configured to perform gas chromatography (GC), gaschromatography-mass spectrometry (GCMS), liquid chromatography (LC),liquid chromatography-mass spectrometry (LCMS) or some other form ofchemical analysis, including other forms of chromatography (e.g.,detector 140 can be a mass spectrometer for detecting samples passingthrough the chemical analysis device 160, such as a quadrupole massspectrometer). The sample extraction device 100 can house a sample thatwas previously collected in a sample collection process, as will bedescribed below with reference to FIGS. 2-3, for example.

In some examples, the chemical analysis device 160 can desorb samplefrom the sample extraction device 100 using a thermal desorberconfiguration that will now be described. Specifically, in someexamples, the chemical analysis device 160 can include, divert vent 156,pre-column 162, primary column 164, injector 166, pressure controller168, thermal desorption device 101 into which sample extraction device100 can be inserted for desorbing sample into chemical analysis device160, and a plurality of valves 172-178. In some examples, injector 166can be a capped-off GC injector.

The desorption device 101 can be made of stainless steel and canoptionally be lined with ceramic, and can include a replaceable liner154 and heat sink 158. The replaceable liner 154 can improve transfer ofsample from the sample extraction device 100 to the pre-column 162 andprimary column 164 of chemical analysis device 160 without (or withminimal) chemical reactions, for example. Further, liner 154 can includechannel 152 to fluidly couple the sample extraction device 100 to thechemical analysis device 160. In some examples, heat sink 158 canprotect rubber seals 108 between the sample extraction device 100 andthe desorption device 101 from excessive heat exposure and/or chemicaloutgassing. As an example, the rubber seals 108 can be included in thesample extraction device, as will be described below with reference toFIGS. 2A-2C.

In some examples, during the chemical analysis process (e.g., GC, GCMS,LC, or LCMS), the first valve 172 can control flow of a carrier fluidfrom pressure controller 168 through sorbent inside sample extractiondevice 100 for transfer of sample from the sample extraction device 100to the pre-column 162 and primary column 164. The first valve 172 can befluidly coupled to the sample extraction device 100 by way of port 132of the sample extraction device 100, for example. Depending on thechemical analysis procedure and in the disclosed configuration, thecarrier fluid can be a gas (e.g., for GC or GCMS), though it isunderstood that in some configurations, the carrier fluid can be aliquid (e.g., for LC or LCMS). The second valve 174 can control the flowof fluid around (e.g., bypassing) the sample extraction device 100 intochannel 152 during preheating and can also be used to check for leaksbetween the sample extraction device 100 and desorption device 101, forexample. In some examples, the third valve 176 can control flow of fluid(flowing into sample extraction device 100 via the first valve 172)directly out a split vent 177 to precisely and reproducibly reduce theamount of sample transferred to the pre-column 162 and primary column164 and/or to increase sample injection rates into the chemical analysisdevice 160. The fourth valve 178 can control flow of fluid out from adivert vent 156 downstream of the pre-column 162 for either high flowpre-column enrichment without splitting, or backflushing to preventcontamination of the primary column 164 with heavier contaminants, forexample.

Upon desorption of the sample, the sample can pass through thepre-column 162 and the column 164 at a rate controlled by controller 168by way of controlling the pressure of carrier gas. As the sample flowsthrough the pre-column 162 and column 164, various compounds of thesample can move at different rates depending on compound mass, forexample. In some examples, the sample can exit column 164 to enter thedetector device 140, which can be used to identify the relativeconcentrations of compounds present in the sample based on time ofarrival at the detector device 140 and by the mass fragmentation patternof the compounds when using a mass spectrometer. In this way, thecomposition of the sample can be determined.

FIG. 1B illustrates an exemplary process 180 for performing a chemicalanalysis procedure using sample extraction device 100, desorption device101, chemical analysis device 160, and detector 140 according toexamples of the disclosure. As an example, the chemical analysis processcan be GCMS. To perform GCMS, the pressure controller 168 can supply acarrier gas, such as helium, nitrogen, or some other inert ornon-reactive gas, which can flow through sorbent inside sampleextraction device 100 and into pre-column 162 to facilitate sampleextraction from the sorbent.

Initially, in step 182, the second valve 174 can be open, for example.In some examples, the sample extraction device 100 can be inserted intothe desorption device 101 in step 184 while second valve 174 is open.Next, in step 186, a pre-heat can occur while second valve 174 is open.In some examples, the pre-heat can take zero to three minutes, thoughother lengths of time are possible. After the pre-heat, the second valve174 can be closed in step 188 and the first valve 172, which can befluidly coupled to the sample extraction device 100 by way of port 132of the sample extraction device 100, can be opened in step 190. Theclosing of second valve 174 and the opening of first valve 172 can causethe desorption of the sample in step 192, for example. In some examples,at step 194, the third valve 176 can be opened to optionally perform asplit injection. Performing a split injection can precisely andreproducibly reduce the amount of sample transferred to the column andincrease injection rates, for example. In some examples, the third valve176 is left open and the fourth valve 178 is opened in step 196 toimprove transfer of heavy sample chemicals to the pre-column 162 whileexcess gas flows out from the fourth valve 178. Alternatively, in someexamples, the third valve 176 can be left closed during sampledesorption steps 192-196 to achieve complete transfer of heavy compoundsinto the pre-column 162. After desorption, if the fourth valve 178 hadbeen opened in step 196, it can be closed in step 198, for example. Thethird valve 176 can open or remain open to remove any residual sampleleft in the sample extraction device 100 during a bake out process toclean the sample extraction device 100 for reuse in another sampleanalysis. In some examples, sample extraction device 100 can be reusedhundreds of times in this way.

FIG. 2A illustrates an exemplary sample extraction device 200 accordingto examples of the disclosure. In some examples, sample extractiondevice 200 can correspond to sample extraction device 100 in FIGS.1A-1B, and can be used for chemical analysis in a manner similar to thatdescribed with respect to FIGS. 1A-1B. As an example, sample extractiondevice 200 can have a diameter between 1/32 in. and ⅜ in. (e.g., theexternal or internal diameter of the sample extraction device); in someexamples, the diameter of sample extraction device 200 can be as smallas the diameters of the capillary columns (e.g., pre-column 162 and/orcolumn 164) in the chemical analysis device. In some examples, otherdimensions are possible. Sample extraction device 200 can comprise atube-like structure, for example, that includes various channels and/orcavities as will be described below. In some examples, sample extractiondevice 200 can be fabricated from stainless steel or another suitablematerial (e.g., a material that is substantially inert). All or part ofthe surface of sample extraction device 200 can be coated with achemical vapor deposition (CVD)-deposited ceramic to increase theinertness of the sample extraction device 200, for example. Othercoatings that similarly increase the inertness of the sample extractiondevice 200 can similarly be used.

Sample extraction device 200 can include lower cavity 220. In someexamples, the lower cavity 220 can contain a sorbent 202, which can be,for example, an adsorbent or an absorbent. The sorbent can be Tenax TA,Tenax/Carboxen, a short piece of 0.53 mm ID porous layer open tubular(PLOT) column ranging in composition from polydimethylsiloxane (PDMS),PLOT 0, and/or carboxen, or some other sorbent that can be chosen basedon the sample(s) to be collected by the sample collection device 200,for example. As will be described below, in some examples, sorbent 202can be selected to collect a sample for analysis. In some examples, thesorbent 202 can be located towards an extraction end 212 of the sampleextraction device 200. That is to say, sorbent 202 can be closer to theextraction end 212 of the sample extraction device 200 than it is to avalve end 214 of the sample extraction device. Extraction end 212 of thesample extraction device 200 can be open to the environment of thesample extraction device such that the sample being collected can enterlower cavity 220, and can adsorb or absorb to sorbent 202, as will bedescribed in more detail below.

At the valve end 214 of the sample extraction device 200 (e.g., oppositeextraction end 212 of the sample extraction device 200), the sampleextraction device 200 can include a sealing plunger 204, a spring 205,and an internal seal 206, for example. The internal seal 206 can be afluoroelastomer seal, a perfluoroelastomer seal, or any other suitableseal, for example. In some examples, sealing plunger 204 and internalseal 206 can selectively restrict fluid (e.g., gas, liquid, etc.) flowthrough internal channel 230 between sealing plunger 204/internal seal206 and lower cavity 220/sorbent 202. For example, when sealing plunger204 is pressed up against seal 206, fluid flow through sample extractiondevice 200 can be restricted, and when sealing plunger 204 is moved awayor otherwise separated from seal 206, fluid flow through sampleextraction device 200 may be unrestricted. In some examples, sealingplunger 204 can be tensioned via spring 205 against seal 206 such thatin a default configuration, sealing plunger 204 can be pressed upagainst seal 206 and fluid flow through sample extraction device 200 canbe restricted. In some examples, spring 205 can be fabricated from anon-reactive material, such as 316 stainless steel coated with a ceramicmaterial using a chemical vapor deposition (CVD) process. Fluid flow(e.g., air being drawn into a vacuum source) through sample extractiondevice 200 can be allowed by causing sealing plunger 204 to move awayfrom seal 206 (e.g., via mechanical means such as a pin from above, orother means). For example, a vacuum source can be coupled to the sampleextraction device 100 at the valve end 214 to open sealing plunger 204and draw a vacuum through sealing plunger 204, an internal channel 230,and lower cavity 220. Additionally, in some examples, sealing plunger204 can remain open (e.g., during continuous vacuum evacuation) toevaporate unwanted matrix, such as water or alcohol, from the samplethrough sorbent 202.

As an example, during a sample extraction process in which a sample canbe collected in sample extraction device 200, as will be described inmore detail below, a vacuum can be drawn through sealing plunger 204,internal channel 230 and lower cavity 220 to facilitate samplecollection by sorbent 202 in lower cavity 220. In some examples, afterthe sample has been collected by sample extraction device 200, thesealing plunger 204 can be opened to release the vacuum. However,releasing the vacuum by opening sealing plunger 204 can cause air to bepushed through sorbent 202. Thus, in some examples, the vacuum is notreleased via sealing plunger 204—rather, the sample extraction device200 can simply be removed from the environment containing the sample(e.g., a sample vial) without releasing the vacuum, which can preventair from entering the sorbent 202 and prevent backflushing of thesorbent 202 which can cause loss of adsorbed/absorbed compounds.Additionally, in some examples, after the sample has been collected bythe sample extraction device 200, the sealing plunger 204 can be remainclosed (e.g., as it can be during sample collection) and can isolate thesample from the environment, allowing the sample to be stored in thesample extraction device 200 between extraction and analysis. Forexample, spring 205 can cause the sealing plunger 204 to remain closedin the absence of a mechanical force to open sealing plunger 204. Duringstorage, the sample extraction device 200 can be kept in an isolationsleeve to avoid contaminating the sample. Subsequently, in someexamples, during the chemical analysis process, a carrier fluid can bedrawn through sealing plunger 204, into internal channel 230 and lowercavity 220, and into chemical analysis device 160, allowing for rapiddesorption of the sample from sorbent 202 into the chemical analysisdevice 160. Additionally or alternatively, in some examples, during thechemical analysis process, the carrier fluid can be drawn through port232 (e.g., instead of through sealing plunger 204), into internalchannel 230 and lower cavity 220, and into chemical analysis device 160.In some examples, port 232 can be a channel in fluid communication withlower cavity 220 and the outside of sample extraction device 200.Preferably, the open end of port 232 can be located between externalseals 208 so that port 232 can be sealed when the sample extractiondevice 100 is sealed against another object (e.g., a desorption deviceor sample vial), for example. In some examples, other locations onsample extraction device 200 are possible.

The sample extraction device 200 can further include one or moreexternal seals 208, for example. The external seals 208 can be made ofan elastomeric material and can be fluoroelastomer seals orperfluoroelastomer seals. In some examples, the external seals 208 canbe Viton™ seals or other suitable seals. The external seals 208 can belocated externally on sample extraction device 200 between ends 212 and214. The external seals 208 can include one or more gaskets or o-ringsfitted around the outside of the sample extraction device 200, forexample. In some examples, the external seals 208 can be used to form aseal between sample extraction device 200 and a sample vial into whichsample extraction device 200 can be inserted during a sample extractionprocess (which will be described with reference to FIG. 2B), and/or toform a seal between sample extraction device 200 and desorption device101 into which sample extraction device 200 can be inserted during asample desorption process (as described previously).

FIG. 2B illustrates an exemplary manner of extracting a sample from asample vial 250 that includes sample 252 using sample extraction device200 according to examples of the disclosure. In some examples, samplevial 250 can include a wall with a void into which sample extractiondevice 200 can be inserted, as shown (e.g., partially inserted intosample vial 250 such that extraction end 212 of sample extraction device200 is inside sample vial 250, and valve end 214 of sample extractiondevice 200 remains outside of sample vial 250). Insertion of sampleextraction device 200 into sample vial 250 can create a seal, atexternal seals 208, between sample extraction device 200 and sample vial250 such that vacuum can be maintained inside sample vial 250 whilesample extraction device 200 is inserted into sample vial 250. Samplevial 250 can contain a sample 252 and headspace gas 254, for example.Headspace gas 254 can include one or more compounds evaporated fromsample 252. In some examples, sample 252 can be a liquid sample or asolid sample. Sample extraction device 200, seals 208, sample vial 250and/or sample 252 can be configured such that when sample extractiondevice 200 is inserted into sample vial and sealed against sample vial250, extraction end 212 of sample extraction device 200 can bepositioned within headspace gas 254, above sample 252 (e.g., notpositioned inside sample 252).

In some examples, while the sample extraction device 200 is insertedinto sample vial 250, a vacuum can be pulled in sample vial 250 throughthe sample extraction device 200 by way of internal sealing plunger 204(e.g., vacuum can be pulled through internal sealing plunger 204,internal channel 230 and lower cavity 220 containing sorbent 202). Bypulling the vacuum through the sample extraction device 200 in this way,the evacuated headspace gas 254—which, in some examples, can include thesample of interest—can be absorbed or adsorbed by sorbent 202 in sampleextraction device 200, as opposed to being lost as a result of bypulling vacuum in some other way (e.g., through a separate opening ofthe sample vial 250). In some examples, most (e.g., 99 percent or more)of the sample 252 can be in the solid or liquid phase when the vacuum isdrawn, meaning the vacuum can mostly draw air, rather than evaporatedsample, through sorbent 202. Thus, in some examples, it can bebeneficial to draw vacuum via sample extraction device 200, remove thevacuum source, and leave extraction device 200 inside sample vial 250 inthe vacuum-drawn state for a period of time to collect sample 252 insorbent 202, as will be described in more detail below. The sampleextraction device 200 can continue to hold the vacuum after the vacuumsource is released, as previously described. During this time, thesample can continue to enter the gas phase and be collected by sorbent202, as will now be described.

A vacuum source can pull the vacuum through the sample extraction device200 for about 10-60 seconds, for example. The external seals 208 andinternal seal 204 of the sample extraction device 200 can hold thevacuum even after the vacuum source has been removed. In some examples,the reduced pressure inside sample vial 250 can cause the sample 252 toenter the gas phase more quickly, allowing for faster sample 252extraction into sorbent 202 compared to collection of sample 252 athigher pressures. Specifically, once under vacuum, sample 252 can, viadiffusion, find its way to sorbent 202. Many compounds can be more than99% in the liquid or solid phase while the vacuum is being drawn andlater enter the gas phase under the vacuum held by sample extractiondevice 200, for example. Once in the gas phase, the sample can enter thesample extraction device 200 and remain trapped by the sorbent 202. Insome examples, the sample extraction device 200 can remain in the samplevial 250 holding a vacuum and extracting sample for anywhere from a fewminutes to several days (e.g., 10 minutes to 1-2 days). The evaporationand collection of the sample can occur more quickly under vacuum than itwould under atmospheric or other elevated pressures. Additionally, insome examples, sample extraction can be performed at elevatedtemperatures (e.g., 25° C. or 100° C.) to further improve extractiontimes. Such ability to extract sample 252 using sample extraction device200 under vacuum for extended periods of time can allow significantsample 252 to build up in sorbent 202, which can allow sample extractiondevice 200 to collect, and subsequent chemical analysis processes todetect, sufficient amounts of even very low-level compounds in sample252.

A number of factors can be considered in selecting extractiontemperature and extraction time for a given sample. For example, somecompounds have a low vapor pressure and a high boiling point and may beextracted at a higher temperature and/or for a longer time thancompounds with a higher vapor pressure and a lower boiling point. Insome examples, “exhaustive extraction” can be performed in which thevacuum is held in the sample vial 250 and extraction is allowed to occuruntil all volatile chemicals have been extracted from sample 252.“Exhaustive extraction” can be highly reproducible because the liquid orsolid sample 252 can be weighed prior to extraction, and several trialscan be prepared using the same weight of sample.

Extracting sample under vacuum using sample extraction device 200 canhave several advantages. For example, vacuum extraction performed over along integration time can better recover low-volatility compounds thanpossible by other methods. Additionally, the diffusive sample extractionprocess disclosed herein (i.e., extracting sample 252 under vacuumconditions) can improve recovery of heavy compounds (e.g., improvedability to desorb those compounds from sorbent 202 into the chemicalanalysis device or otherwise) due to reduced channeling into the sorbent202, as compared to methods that rely on a carrier gas to deliver thesample to a sorbent bed. Additionally, performing sample extractionunder vacuum as described (e.g., such that sample 252 has transitionedto the gas phase and is under vacuum) can allow molecules of sample tofind the extraction end 212 of sample extraction device 200 (and thussorbent 202) much faster than they would otherwise in non-vacuumconditions, increasing the rate of extraction, due to reduced gas phasecollisions resulting in faster net diffusion rates in the sample vial250. In some examples, the vacuum extraction of the disclosure can allowrecovery of heavier compounds without applying heat during the sampleextraction process, allowing natural and biological samples to beanalyzed without breakdown of the sample, which can produce artifactsthat were not in the original sample. Samples such as foods, beverages,blood, urine, breath condensate, and other samples that may not tolerateelevated temperatures can be sampled by vacuum extraction at roomtemperature or another non-elevated temperature, for example.

In some examples, the sample collected using the vacuum-assistedextraction techniques and sample extraction device 200 of the disclosurecan remain captured towards the outermost edge of the sorbent 202 (i.e.,proximate to the edge of sorbent 202 directly exposed to sample 252 atthe extraction end 212 of the sample extraction device 200), rather thanbeing driven deep into sorbent 202 due to dynamic extraction of samplepulled into sorbent 202 via gas flow. This tendency of the sample toremain captured towards the outermost edge of sorbent 202 can cause thesample to be desorbed into the desorption device 101 and/or chemicalanalysis device 160 more rapidly, as compared to a sample that is moreevenly distributed through sorbent 202, for example. Further, thistendency can ensure more complete desorption of sample/compounds fromsorbent 202, making it easier to reuse the sample extraction device 200without risk of cross-contamination and/or carryover between uses. Insome examples, the tendency of the sample to collect at the opening ofthe extraction end 212 of the sample extraction device 200 can keep thesample extraction device 200 cleaner, preventing thermal breakdown ofthe sample during desorption, thus increasing the number of reuses ofthe sample extraction device 200. Lastly, the sample extraction device200 can hold large amounts of sorbent 202, thus reducing analyticalvariability even with moderate matrix-related affinity differences ofsample compounds to the liquid or solid sample 252.

While optimal sample extraction may be performed under vacuum orlower-pressure conditions, in some examples, passive sample extractioncan be performed using sample extraction device 200 in non-vacuumconditions inside sample vial 250, and can even be performed outside ofthe sample vial 250 to sample air, for example. Some of the sampleextraction techniques of this disclosure that utilize sample extractiondevice 200 can occur without the use of solvents, making the disclosedextraction techniques “green” (e.g., environmentally friendly).

Once the sample 252 is collected in sorbent 202 inside sample extractiondevice 200, chemical analysis (e.g., GC, GC-MS, or LC) can be performedto determine the composition of the sample, as described herein, forexample. As described above, the sample extraction techniques of thedisclosure can occur “off-line” from the chemical analysis device 160(e.g., performed outside and independent of the chemical analysis device160), thus making sample extraction time independent of the time ittakes to analyze the sample in the chemical analysis device 160.Therefore, sample preparation can occur remotely from the chemicalanalysis device 160, allowing for longer extraction times as needed andfor the extraction and analysis to occur in different locations asneeded. This flexibility in when and where extraction can occur canallow extraction to be optimized, thus improving the sensitivity andversatility of the sample extraction device 200, for example.Additionally, in some examples, the sample collected by sorbent 202 canbe stored in the sample extraction device 200 for some time beforeanalysis occurs.

FIG. 2C illustrates another exemplary sample extraction device 210according to examples of the disclosure. In some examples, sampleextraction device 210 can be similar to sample extraction device 200 andcan correspond to sample extraction device 100 in FIG. 1A to be used ina chemical analysis process similar to that described with respect toFIGS. 1A-1B. Sample extraction device 210 can include similar componentsto sample extraction device 200, such as external seal 209, lower cavity221 with sorbent 203, extraction end 213, and a valve end 215, and caninclude various components of sample extraction device 200 notillustrated in FIG. 2C (e.g., sealing plunger 204 for pulling vacuumand/or selectively allowing solvent flow through the sample extractiondevice 210, spring 205, and internal seal 206), except as otherwisedescribed here. In some examples, sample extraction device 210 can beused to extract samples that require LC or LCMS because they are notstable on a GC or GCMS column, and/or to extract samples that are betterrecovered using a solvent, rather than via thermal desorption prior toGC or GCMS. Accordingly, sample extraction device 210 can be used whensample from sample extraction device 210 is to be recovered using asolvent, whether for GC, GCMS, LC, and/or LCMS, for example. Becausesample extraction device 210 can be used in conjunction with solvent, asdescribed above, sorbent 203 can be a solvent-compatible sorbent.

In addition to components in common with sample extraction device 200,sample extraction device 210 can include threads 211 via which lowercavity 221 (including sorbent 203) can be attached to the remainder ofthe sample extraction device 210, and/or sorbent retention means 207,for example. In some examples, sorbent retention means 207 can be one ormore screens, frits, or seals between which sorbent 203 can be containedin lower cavity 221, and which can confine sorbent 203 within lowercavity 221 such that sorbent 203 will not be expelled from sampleextraction device 210 during solvent-extraction of the sample from thesample extraction device 210. As such, sorbent retention means 207 canbe solvent-transmissive but not sorbent-transmissive. After sampleextraction from sorbent 203 using a solvent (e.g., after the sample hasbeen extracted for analysis by GC, GCMS, LC, and/or LCMS), the lowercavity 221 (including sorbent 203) can be removed for solvent extractionby decoupling the lower cavity 221 from the rest of the sampleextraction device 210 at the threads 211. Solvent extraction can beconducted manually or in an automated manner, for example. In someexamples, automated extraction can occur simultaneously with orsequentially with GC, GCMS, LC, and/or LCMS analysis.

FIG. 3 illustrates an exemplary process 300 for collecting a sample andconducting chemical analysis of the sample according to examples of thedisclosure. In some examples, in step 301 of process 300, the sample canbe prepared. Preparing the sample can include weighing the sample intothe sample vial (e.g., sample vial 250) and placing an appropriate capand lid on the sample vial to allow insertion of a sample extractiondevice (e.g., sample extraction device 100, 200, or 210) into the samplevial, for example. In some examples, in step 302, the clean sampleextraction device can be provided with a sorbent (e.g., sorbent 202).

Next, in step 304, the sample extraction device can be inserted into andcoupled to a sample vial (e.g., sample vial 250) that includes a sample(e.g., sample 252), allowing the sample to be extracted from the samplevial into the sample extraction device. The sample extraction device canbe sealed to the sample vial by an external seal (e.g., external seal208) of the sample extraction device, for example. In some examples, instep 306, a vacuum can be drawn in the sample vial through a valve(e.g., sealing plunger 204), and thus via internal channel (e.g.,internal channel 230) and lower cavity (e.g., lower cavity 220)—whichcan include a sorbent (e.g., sorbent 202)—of the sample extractiondevice. To draw the vacuum, a vacuum source can be coupled to the top(e.g., valve end 214) of the sample extraction device, for example.Next, in step 308, after enough time has passed to create a vacuum inthe sample vial, the vacuum source can be removed. In some examples,during step 308, even after sufficient vacuum is reached, the vacuumsource can remain coupled to sample extraction device and evacuation ofthe sample vial can continue for a period of time to boil off some ofthe matrix in the sample (e.g., water or alcohol). After the vacuumsource is removed, the vacuum can be held by the sample extractiondevice (e.g., using internal seal 206 and external seals 208). In someexamples, in step 310, heat can be applied to the sample vial (e.g., insome examples, anywhere from 4 degrees Celsius to 150 degrees Celsius,and typically 25 degrees Celsius).

In some examples, steps 304 and/or 306 can be skipped; for example,rather than being coupled to a sample vial, the sample extraction devicecan collect a sample from the surrounding air (e.g., the air in theenvironment of the sample extraction device); in some examples, thesample extraction device can be coupled to the sample vial and samplecan be collected at atmospheric pressure in the sample vial—that is,step 306 can be skipped. In some cases of air analysis for indoor oroutdoor air monitoring, the sample extraction device can collect samplefor up to two weeks to determine an average concentration of chemicalsin the air.

Once the extraction process has been set up (e.g., by applying a vacuumand/or heat, or by exposing the sample extraction device to air to besampled), extraction can be allowed to occur in step 312. In someexamples, the sample vial can remain under vacuum and applied heat for apredetermined amount of time, or until “exhaustive extraction” occurs.For example, the process can remain at step 312 for anywhere from oneminute to two days depending on the compounds to be analyzed. After thesample is collected in the sample extraction device, the sampleextraction device can be placed in an isolation sleeve at step 314 toprevent contamination of the sample during storage. Later, at step 316,the sample extraction device can be coupled to a chemical analysisdevice (e.g., chemical analysis device 160). At step 318, fluid can beflowed through the sample extraction device, including through the lowercavity of the sample extraction device, which includes the collectedsample and a sorbent, to facilitate desorption of the sample into thechemical analysis device, which can perform GC, GCMS, LC, LCMS, or someother analysis procedure to evaluate one or more characteristics of thesample, such as its composition. After chemical analysis is complete,the sample extraction device can be placed in an isolation sleeve atstep 320 so that it remains clean until the next extraction.

As such, the examples of the disclosure provide an improved sampleextraction device and method for extracting sample from, for example, aliquid or solid contained in a sample vial, and desorbing such sampleinto a chemical analysis device for analysis.

Therefore, according to the above, some examples of the disclosure arerelated to a cavity configured to contain a sorbent, the cavity havingan opening at an extraction end of the sample extraction device; and aninternal seal configured to selectively restrict fluid flow through thecavity, the internal seal disposed at a valve end of the sampleextraction device. Additionally or alternatively, in some examples, thesorbent is disposed within the cavity such that it is closer to theopening at the extraction end of the sample extraction device than it isto a valve end of the cavity. Additionally or alternatively, in someexamples, the sample extraction device further comprises an externalseal disposed around an outside of the sample extraction device.Additionally or alternatively, in some examples, the external sealcomprises a fluoroelastomer seal or a perfluoroelastomer seal.Additionally or alternatively, in some examples, the external seal isconfigured to form a seal between the sample extraction device and asample vial into which the sample extraction device is inserted.Additionally or alternatively, in some examples, the internal seal isconfigured to facilitate pulling vacuum in the sample vial through thecavity and the sorbent, the vacuum pulled by a vacuum source coupled tothe sample extraction device at the valve end. Additionally oralternatively, in some examples, the internal seal is configured tofacilitate pulling headspace gas that is inside the sample vial into thecavity and the sorbent. Additionally or alternatively, in some examples,the external seal is disposed at a location on the sample extractiondevice such that, when the sample extraction device is inserted into thesample vial, the extraction end of the sample extraction device isinside a headspace gas in the sample vial. Additionally oralternatively, in some examples, the internal seal maintains a vacuuminside the sample vial after removal of the vacuum source from thesample extraction device. Additionally or alternatively, in someexamples, the external seal is configured to form a seal between thesample extraction device and a chemical analysis device into which thesample extraction device is inserted. Additionally or alternatively, insome examples, the internal seal is configured to facilitate flowingfluid through the cavity and the sorbent and into the chemical analysisdevice. Additionally or alternatively, in some examples, the sampleextraction device further comprises a port configured to facilitateflowing fluid through the cavity and the sorbent and into the chemicalanalysis device. Additionally or alternatively, in some examples, theinternal seal is configured to isolate sample, collected in the sorbent,from an environment of the sample extraction device after a sampleextraction process. Additionally or alternatively, in some examples, thecavity is removably coupled to the sample extraction device, and thecavity further comprises one or more sorbent retention devicesconfigured to retain the sorbent within the cavity.

Some examples of the disclosure are related to a method comprisingcoupling a sample vial to a sample extraction device via an externalseal of the sample extraction device, wherein the sample vial includes asample and a headspace gas, the sample comprising one or more of a solidand a liquid; drawing a vacuum in the sample vial through an internalseal of the sample extraction device, such that in the process ofdrawing the vacuum, the headspace gas is drawn through a sorbentincluded in the sample extraction device; and collecting the sample inthe sorbent included in the sample extraction device while the vacuum isdrawn in the sample vial.

Some examples of the disclosure are related to a method comprisingcoupling a sample vial to a sample extraction device via an externalseal of the sample extraction device, wherein the sample vial includes asample, the sample comprising one or more of a solid and a liquid;coupling a vacuum source to the sample extraction device; drawing avacuum, with the vacuum source, in the sample vial through an internalseal of the sample extraction device for a first period of time, suchthat in the process of drawing the vacuum, the vacuum is drawn through asorbent included in the sample extraction device; removing the vacuumsource after the vacuum is drawn; after removing the vacuum source,collecting the sample in the sorbent included in the sample extractiondevice, for a second period of time, while the vacuum is held in thesample vial. Additionally or alternatively, in some examples, the methodfurther includes after collecting the sample, decoupling the sampleextraction device from the sample vial; coupling the sample extractiondevice to a column of a chemical analysis device; and passing a carrierfluid through a port on the sample extraction device seal and thesorbent of the sample extraction device and into the column of thechemical analysis device. Additionally or alternatively, in someexamples, the chemical analysis device is configured to perform one ormore of gas chromatography, gas chromatography—mass spectrometry, liquidchromatography, and liquid chromatography-mass spectrometry on thesample. Additionally or alternatively, in some examples, the methodfurther includes after decoupling the sample extraction device from thesample vial and prior to coupling the sample extraction device to thecolumn of the chemical analysis device and passing the carrier fluidthrough the internal seal of the sample extraction device: sealing thesample extraction device; an storing the sample extraction device.Additionally or alternatively, in some examples, the method furtherincludes one or more of adsorbing and absorbing the sample into thesorbent while collecting the sample in the sorbent. Additionally oralternatively, in some examples, the method further includes eluting thesample from the sorbent using a solvent to form an extract; andinserting the extract into a chemical analysis device to perform one ormore of gas chromatography, gas chromatography-mass spectrometry, liquidchromatography, and liquid chromatography-mass spectrometry on theextract. Additionally or alternatively, in some examples, the firstperiod of time lasts until one or more of water and alcohol areeliminated from the sample. Additionally or alternatively, in someexamples, the second period of time lasts until sufficient extraction ofthe liquid or solid sample has occurred, until equilibrium between thesample extraction device and the contents of the sample vial has beenachieved, or until complete extraction of GC or LC compatible compoundsfrom the sample in the sample vial has been achieved.

Although examples have been fully described with reference to theaccompanying drawings, it is to be noted that various changes andmodifications will become apparent to those skilled in the art. Suchchanges and modifications are to be understood as being included withinthe scope of examples of this disclosure as defined by the appendedclaims.

1. A method comprising: providing a sorbent in a headspace of a system,the sorbent disposed within a tube, and the system containing a sample;drawing a vacuum in the system with a vacuum source; and after drawingthe vacuum with the vacuum source and while the vacuum is maintained inthe system, causing transfer of one or more volatile compounds of thesample to the sorbent for subsequent chemical analysis.
 2. The method ofclaim 1, further comprising after transferring the one or more volatilecompounds of the sample to the sorbent, chemically analyzing the one ormore volatile compounds that are in the sorbent.
 3. The method of claim2, wherein the chemically analyzing includes transferring the one ormore volatile compounds from the sorbent via thermal desorption.
 4. Themethod of claim 2, wherein the chemically analyzing includestransferring the one or more volatile compounds from the sorbent viasolvent extraction.
 5. The method of claim 1, wherein the system is aclosed system.
 6. The method of claim 1, wherein the system comprises asample vial.
 7. The method of claim 1, further comprising: aftertransferring the one or more volatile compounds of the sample to thesorbent for subsequent chemical analysis, removing the one or morevolatile compounds of the sample from the sorbent such that no volatilecompounds remain in the sorbent and re-using the sorbent to collect oneor more volatile compounds of a second sample different than the sample.8. The method of claim 1, further comprising: sealing the system.
 9. Themethod of claim 1, wherein the vacuum is maintained in the system andtransfer of the one or more volatile compounds of the sample to thesorbent occurs during a period of time is in the range of one minute totwenty-four hours.
 10. The method of claim 1, wherein the vacuum ismaintained in the system and at least partial transfer of the one ormore volatile compounds of the sample to the sorbent occurs during aperiod of time is in the range of ten minutes to 16 hours.
 11. Themethod of claim 1, wherein the vacuum is maintained in the system andthe transfer of the one or more volatile compounds of the sample to thesorbent occurs until equilibrium is reached between the sorbent and thesample.
 12. A system, comprising: a sample vial; a sorbent configured tobe placed in a headspace of the sample vial, the sorbent disposed withina tube; means for drawing a vacuum in the sample vial; and means for,after the vacuum is drawn in the system and while the vacuum ismaintained in the system, causing transfer of one or more volatilecompounds of the sample to the sorbent for subsequent chemical analysis.13. A sample extraction device, comprising: a port configured to accepta vacuum source; and a sorbent coupled to the port, the sorbent disposedwithin a tube and configured to, after drawing, with the vacuum source,a vacuum in a system containing the sorbent and a sample, and while thevacuum is maintained in the system, cause one or more volatile compoundsof the sample to transfer to the sorbent for subsequent chemicalanalysis including thermal desorption or solvent extraction.
 14. Thesample extraction device of claim 13, wherein the system is a closedsystem.
 15. The sample extraction device of claim 13, wherein the systemcomprises a sample vial.
 16. The sample extraction device of claim 13,wherein: the sorbent is configured to be re-used to collect one or morevolatile compounds of a second sample different from the sample aftertransferring the one or more volatile compounds of the sample to thesorbent for subsequent chemical analysis, and removing the one or morevolatile compounds of the sample from the sorbent such that no volatilecompounds remain in the sorbent.
 17. The sample extraction device ofclaim 13, wherein the vacuum is maintained in the system and transfer ofthe one or more volatile compounds of the sample to the sorbent occursduring a period of time is in the range of one minute to twenty-fourhours.
 18. The sample extraction device of claim 13, wherein the vacuumis maintained in the system and at least partial transfer of the one ormore volatile compounds of the sample to the sorbent occurs during aperiod of time is in the range of ten minutes to 16 hours.
 19. Thesample extraction device of claim 13, wherein the vacuum is maintainedin the system and the transfer of the one or more volatile compounds ofthe sample to the sorbent occurs until equilibrium is reached betweenthe sorbent and the sample.